Charakterisierung der Rolle von MigA während der Mitose und des polaren Wachstums in Aspergillus nidulans

Nachweis eines aktiven Mikroutubuli Führungsmechanismus in Aspergillus nidulans

electrochemical properties, electronic structures and catalysis

A mesoionic carbene with a ferrocene backbone is used as a metalloligand to generate the first example of their Fe–Au heterobimetallic complexes. The details of geometric and electronic structures in different redox states and preliminary catalytic results are presented

Overexpression of the Potato Monosaccharide Transporter StSWEET7a Promotes Root Colonization by Symbiotic and Pathogenic Fungi by Increasing Root Sink Strength

Root colonization by filamentous fungi modifies sugar partitioning in plants by increasing the sink strength. As a result, a transcriptional reprogramming of sugar transporters takes place. Here we have further advanced in the characterization of the potato SWEET sugar transporters and their regulation in response to the colonization by symbiotic and pathogenic fungi. We previously showed that root colonization by the AM fungus Rhizophagus irregularis induces a major transcriptional reprogramming of the 35 potato SWEETs, with 12 genes induced and 10 repressed. In contrast, here we show that during the early colonization phase, the necrotrophic fungus Fusarium solani only induces one SWEET transporter, StSWEET7a, while represses most of the others (25). StSWEET7a was also induced during root colonization by the hemi-biotrophic fungus Fusarium oxysporum f. sp. tuberosi. StSWEET7a which belongs to the clade II of SWEET transporters localized to the plasma membrane and transports glucose, fructose and mannose. Overexpression of StSWEET7a in potato roots increased the strength of this sink as evidenced by an increase in the expression of the cell wall-bound invertase. Concomitantly, plants expressing StSWEET7a were faster colonized by R. irregularis and by F. oxysporum f. sp. tuberosi. The increase in sink strength induced by ectopic expression of StSWEET7a in roots could be abolished by shoot excision which reverted also the increased colonization levels by the symbiotic fungus. Altogether, these results suggest that AM fungi and Fusarium spp. might induce StSWEET7a to increase the sink strength and thus this gene might represent a common susceptibility target for root colonizing fungi

Arbuscular mycorrhiza symbiosis induces a major transcriptional reprogramming of the potato SWEET sugar transporter family

Biotrophic microbes feeding on plants must obtain carbon from their hosts without killing the cells. The symbiotic Arbuscular mycorrhizal (AM) fungi colonizing plant roots do so by inducing major transcriptional changes in the host that ultimately also reprogram the whole carbon partitioning of the plant. AM fungi obtain carbohydrates from the root cortex apoplast, in particular from the periarbuscular space that surrounds arbuscules. However, the mechanisms by which cortical cells export sugars into the apoplast for fungal nutrition are unknown. Recently a novel type of sugar transporter, the SWEET, able to perform not only uptake but also efflux from cells was identified. Plant SWEETs have been shown to be involved in the feeding of pathogenic microbes and are, therefore, good candidates to play a similar role in symbiotic associations. Here we have carried out the first phylogenetic and expression analyses of the potato SWEET family and investigated its role during mycorrhiza symbiosis. The potato genome contains 35 SWEETs that cluster into the same four clades defined in Arabidopsis. Colonization of potato roots by the AM fungus Rhizophagus irregularis imposes major transcriptional rewiring of the SWEET family involving, only in roots, changes in 22 of the 35 members. None of the SWEETs showed mycorrhiza-exclusive induction and most of the 12 induced genes belong to the putative hexose transporters of clade I and II, while only two are putative sucrose transporters from clade III. In contrast, most of the repressed transcripts (10) corresponded to clade III SWEETs. Promoter-reporter assays for three of the induced genes, each from one cluster, showed re-localization of expression to arbuscule-containing cells, supporting a role for SWEETs in the supply of sugars at biotrophic interfaces. The complex transcriptional regulation of SWEETs in roots in response to AM fungal colonization supports a model in which symplastic sucrose in cortical cells could be cleaved in the cytoplasm by sucrose synthases or cytoplasmic invertases and effluxed as glucose, but also directly exported as sucrose and then converted into glucose and fructose by cell wall-bound invertases. Precise biochemical, physiological and molecular analyses are now required to profile the role of each potato SWEET in the arbuscular mycorrhizal symbiosis

Glacial Discharge and its Impact on Phytoplankton Taxonomic Composition in an Antarctic Fjord

The influence of glacial discharge on phytoplankton community composition remains an open question. The Antarctic Peninsula fjords offer an ideal system to understand the effect of ice-ocean forcing on phytoplankton community, providing an extreme in the spatial gradient from the glacio-marine boundary to the Western Antarctic Peninsula (WAP) continental shelf. In Andvord Bay, we found that glacial meltwater input altered surface salinity and was enriched in dissolved iron and nitrate, supporting phytoplankton biomass. The three major groups of phytoplankton fueled by glacial input were: cryptophytes, diatoms, and a group of unidentified small flagellates. In December, cryptophytes dominated the phytoplankton community and were correlated with relatively warmer temperatures in the surface layer; in addition, contrary to our hypothesis, no diatom bloom was observed in the fjord in spite of dissolved iron concentration >1 nM. By April, after the growth season, the overall phytoplankton abundance had decreased by an order of magnitude. Phytoplankton, in particular diatoms, were then limited by daytime length despite abundant macro-nutrient and iron concentrations. Mixed flagellates emerged as the dominant group during April due to the decline of other major taxa. Deep-learning algorithms for predicting the abundance of each major phytoplankton group captured the effects of these environmental factors on the phytoplankton community. Our results show that the fjord, under the influence of glacial meltwater, has relatively high phytoplankton biomass combined with high macro- and trace nutrient concentrations when compared to other WAP regions influenced by sea ice melting. Based on this study, we confirm that flagellates can be the dominant taxon in Antarctic fjords and we propose that iron concentration alone is insufficient to predict diatom growth. Furthermore, buoyant meltwater plumes can enrich the fjord with nitrate even if the main circulation is not driven by glacier meltwater discharge. As glacial meltwater continues to alter the phytoplankton taxonomic composition, it will have an important implication for higher trophic levels and add significant uncertainties to the prediction of regional ecosystem dynamics and biogeochemistry.Fil: Jack Pan, B.. University of California at San Diego. Scripps Institution of Oceanography; Estados UnidosFil: Vernet, Maria. University of California at San Diego. Scripps Institution of Oceanography; Estados UnidosFil: Manck, Lauren. University of California at San Diego. Scripps Institution of Oceanography; Estados UnidosFil: Forsch, Kiefer. University of California at San Diego. Scripps Institution of Oceanography; Estados UnidosFil: Ekern, Lindsey. University of California at San Diego. Scripps Institution of Oceanography; Estados UnidosFil: Mascioni, Martina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Ficología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Barbeau, Katherine. University of California at San Diego. Scripps Institution of Oceanography; Estados UnidosFil: Almandoz, Gaston Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Ficología; ArgentinaFil: Orona, Alexander James. Ocean Motion Technologies; Estados UnidosOcean Sciences Meeting 2020Estados UnidosOcean Sciences Meetin

Ein implantierbares Telemetriesystem zur Impedanzspektroskopie

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.Die kontinuierliche Überwachung des intrakorporalen Zustandes von Geweben beispielsweise zur Erkennung ischämischer Vorgänge nach gefäßchirurgischen Eingriffen oder im Rahmen der Rejektionsdiagnostik läßt sich durch bisher vorhandene Meßsysteme nur bedingt erreichen. Speziell die direkte Erfassung sensitiver Gewebeparameter über einen längeren Zeitraum ohne Belastung für den Patienten stellt in diesem Zusammenhang ein Problem dar. In der nachfolgenden Arbeit wird das Konzept eines implantierbaren Telemetriesystems vorgestellt, das die Bewertung des Gewebezustandes über die Messung der frequenzabhängigen Bioimpedanz ermöglicht. Besondere Beachtung wird der Auslegung und Umsetzung der einzelnen Systemkomponenten sowie der Vorstellung erster in vitro Messungen zur Evaluierung des Meßsystems geschenkt

Factors modulating herbivory patterns in Cymodocea nodosa meadows

In coastal marine food webs, seagrass-grazer interactions play a fundamental role in ecological processes by regulating the structure and functioning of plant communities. Therefore, assessing the strength of these seagrass-grazer links and identifying the mechanisms that regulate these relationships are crucial to increasing our understanding of community and ecosystem structure and dynamics. Herbivory on the temperate seagrass Cymodocea nodosa was evaluated in four locations with contrasting abiotic and biotic factors (i.e., depth; meadow size; seagrass shoot density, productivity, and leaf traits; and herbivore presence) using cross-transplantation experiments carried out once per season to account for seasonal variation. Patterns of feeding rates on C. nodosa meadows showed high temporal variability, with peaks occurring in spring and summer. Results indicate that between 46.59% and 74.08% of the annual leaf production is lost to herbivory at the locations sampled in this study. Herbivory rates increased with higher nitrogen content and shoot density for all types of consumers (mesograzers, fishes, and sea urchins). This work highlights the need to integrate the abiotic and biotic factors modulating herbivory patterns, particularly in a foundation species like C. nodosa, for which changes in plant traits and grazer abundance may trigger trophic cascades with far-reaching consequences for associated species.This study was funded by the Spanish national project CTM2011-24482 (SEA-LIVE), by the Junta de Andalucia Excelence Project PRODESCA (P12-RNM-3020)) and by Ser-Cady project (FEDER-UCA18-107451) cofinanced by the 2014–2020 ERDF Operational Programme and by the Department of Economy, Knowledge, Business and University of the Regional Government of Andalusia. We thank Carmen Henares for field assistance

On the Capability of Artificial Neural Networks to Compensate Nonlinearities in Wavelength Sensing

An intelligent sensor for light wavelength readout, suitable for visible range optical applications, has been developed. Using buried triple photo-junction as basic pixel sensing element in combination with artificial neural network (ANN), the wavelength readout with a full-scale error of less than 1.5% over the range of 400 to 780 nm can be achieved. Through this work, the applicability of the ANN approach in optical sensing is investigated and compared with conventional methods, and a good compromise between accuracy and the possibility for on-chip implementation was thus found. Indeed, this technique can serve different purposes and may replace conventional methods

Importance of the chemical defenses and sugars in the feeding preference of Paracentrotus lividus over two sympatric template seagrass species

Herbivory is a fundamental process regulating the functioning of the ecosystems both in land and marine systems. Few decades ago, herbivory was thought to play only a minor role in seagrass dominated areas, while currently its importance has risen. However, the complex interrelationships between seagrasses and their consumers are not yet fully understood. For instance, seagrasses can tune up morphological, biomechanical, nutritional, and chemical traits in order to reduce the palatability of their leaves and therefore curtail tissue losses, but the final tradeoff of such changes may depend on herbivore guilds. This work focuses on the relative importance of nutritional versus chemical traits in the feeding behavior of the sea urchin Paracentrotus lividus, a temperate generalist mesograzer, over two sympatric seagrass species (Cymodocea nodosa and Zostera noltei). To do that, a set of no-choice and multiple-choice feeding assays were conducted using freeze-dried plants agarbased diets (i.e. whole nutritional properties), polar extracts of both species (i.e. soluble sugars and phenolic natural products), purified phenolic natural products, and also three different concentrations of soluble sugars. Later, a chemical identification and quantification of the phenolic natural products present in the extracts were performed to assess their ecological role as deterrents. Results clearly indicated that the feeding behavior of this generalist herbivore, once overlooked the structural, morphological and biomechanical traits, is mainly determined by nutritional properties, while the presence of phenolic compounds has only a minimal effect on its feeding behavior. In addition, although this study showed that sugars had a positive effect over P. lividus consumption rates, we demonstrated for the first time the deterrent properties of rosmarinic acid and the sulphated flavonoids produced by Z. noltei, which were able to reduce the attractive effect of sugars in the feeding preference of this generalist herbivore